The Predictive Value of Baseline Concordant Left Bundle Branch Block Morphology for Success Rate and Clinic Outcomes
Dingkun Lu1, Xiaofei Li1, Haojie Zhu1
1Cardiac Arrhythmia Center, Fuwai Hospital, National Center for Cardiovascular Diseases, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China.
Insights
Concordant left bundle branch block (con-LBBB) morphology predicts higher success rates for left bundle branch pacing cardiac resynchronization therapy (LBBP-CRT). Patients with con-LBBB also show improved echocardiographic response and reduced mortality or heart failure hospitalizations.
Area of Science:
- Cardiology
- Electrophysiology
- Cardiac Imaging
Background:
- Left bundle branch block (LBBB) presents diverse morphologies, including concordant (con-LBBB) and discordant (dis-LBBB) T-wave and QRS complex relationships.
- Understanding these LBBB subtypes is crucial for optimizing cardiac device therapies.
Purpose of the Study:
- To evaluate the impact of baseline LBBB morphology on the efficacy of left bundle branch pacing cardiac resynchronization therapy (LBBP-CRT).
- To determine if LBBB morphology influences LBBP success, echocardiographic response, and long-term clinical outcomes.
Main Methods:
- Prospective enrollment of 110 heart failure patients with LBBB undergoing attempted LBBP-CRT from 2019-2024.
- Classification of baseline LBBB into con-LBBB, dis-LBBB, and non-true LBBB (non-tLBBB) groups.
- Assessment of primary endpoint (echocardiographic response at 6 months) and secondary endpoints (LBBP success, super-response, mortality/heart failure hospitalization).
Main Results:
- LBBP success rates were highest in the con-LBBB group (84.4%), followed by dis-LBBB (71.0%), and non-tLBBB (51.1%).
- Con-LBBB independently predicted higher LBBP success, echocardiographic response, and super-response.
- Con-LBBB was associated with significantly reduced all-cause mortality or heart failure hospitalization during follow-up.
Conclusions:
- Baseline con-LBBB morphology is a significant predictor of successful LBBP-CRT.
- Con-LBBB is associated with favorable echocardiographic and clinical outcomes, including reduced mortality and hospitalizations.
Background:
The left bundle branch block (LBBB) morphology could be divided into concordant LBBB (con-LBBB; T waves concordant with QRS) or discordant LBBB (dis-LBBB; T waves discordant with QRS) types on the basis of the direction of T and QRS main waves except for true or non-true LBBB (non-tLBBB). In this study we aimed to investigate the influence of baseline LBBB morphology on success rate of left bundle branch pacing (LBBP), echocardiographic response, and clinical outcomes in patients who received LBBP-delivered cardiac resynchronization therapy.
Methods:
Consecutive patients with heart failure (HF) and LBBB who attempted to receive LBBP-delivered cardiac resynchronization therapy were prospectively enrolled from 2019 to 2024. Baseline LBBB morphology was identified as con-LBBB, dis-LBBB, and non-tLBBB types. The primary end point was echocardiographic response at 6-month follow-up. Secondary end points included: (1) LBBP success; (2) echocardiographic super-response; (3) all-cause mortality and/or HF hospitalization.
Results:
A total of 110 patients (32 with con-LBBB, 31 with dis-LBBB, and 47 with non-tLBBB) post cardiac resynchronization therapy were included. The LBBP success rate was highest in the con-LBBB group, followed by the dis-LBBB, and non-tLBBB group (84.4% vs 71.0% vs 51.1%; P = 0.007). After adjusting for confounders, con-LBBB was an independent predictor for LBBP success (odds ratio [OR], 3.90 [95% confidence interval (CI), 1.21-12.51]; P = 0.022), echocardiographic response (OR, 4.88 [95% CI, 1.26-18.81]; P = 0.021), and super-response (OR, 3.87 [95% CI, 1.40-10.69]; P = 0.009). During a mean follow-up of 20.2 ± 12.9 months, con-LBBB was associated with decreased all-cause mortality or HF hospitalization (hazard ratio, 0.08 [95% CI, 0.01-0.62]; P = 0.015).
Conclusions:
Baseline con-LBBB might be a useful predictor for LBBP success and favourable clinical outcomes.
